Dredgistg-machine



.iwf/y N.PETERS, PHOTO-LITHOGRAPHER. WASHINGTQN. D. C.

UNiTED STATES PATENT oEEioE.

E. B. BISHOP, OF SHREVEPORT, LOUISIANA..

DEED G'ING-MACHIN E.

Specicaton forming part of Letters Patent No. 19,908, dated April 13, 1858; Reissued July 14,

To all 'whom it may concern:

Be it known that I, E. B. BISHOP, of Shreveport, in the parish of Caddo and State of Louisiana, have invented a new and useful Machine for Deepening the Channels of Rivers and Harbors; and I- do hereby declare thatthe following is a full, clear, and exact description of the same, reference being had to the annexed drawings, making a part of this specification, in which- Figure l, is a vertical section of my improvement, taken in the line (w), (00),-see Fig. 2; the screw not being bisected. Fig. 2, is a Iplan or top view of ditto.

Similar letters of reference indicate corresponding parts in the two figures.

My invention consists in having two screw excavators placed at the bow or front end of a boat; the screws being placed angularly with each other and so arranged that as they are rotated and the boat propelled along, the bed or bottom of the river or harbor will be scooped out and thrown at either side, thereby deepening the channel. The screws are so arranged that they may be raised or lowered as desired; the screws being rotated by a steam engine on the boat; said engine also driving the propeller of the boat.

To enable those skilled in the art to fully understand and construct my invention, I will proceed to describe it.

A, represents a boat which has a flat bottom; and B, is a beam or piece of timber which projects horizontally out in front of the boat and in line with its center.

To the front end of the beam C, a slide D, is fitted. This Slide is fitted in a dovetail guide (a), at the end of the beam, and may be adjusted higher up or lower down on said beam by means of a screw E.

F, F, represent two shafts, the outer ends of which have their bearings in the ends of the slide D. The inner ends of said shafts have their bearings in the front end of the boat A; the journals of the shafts passing through the bows of the boat, and having beveled pinions on them, one on each. The pinions (b), gear into beveled wheels (c), which are placed on the ends of a crank shaft G. The shaft G, being connected by a pitman with the power shaft of a steam engine.

boat and conveyed away thereby.

The boat A, is provided with a propeller,J

which is driven by the engine above referred to.

The two shafts F, F, it will be seen, are placed angularly with each other; the shafts gradually approaching each other from their inner to their outer ends, as shown clearly in Fig. 2. Each shaft F, is provided with spiral iianches (d). These flanches may have any proper pitch, and may be of any suitable width as circumstances may require. It may be advisable to have the shafts F, provided with spiral flanches so arranged that plates of diiferent widths may be bolted to them in order that flanches of greater or less widths may be readily obtained.

By referring to the gearing in Fig. 2, it will be seen that the shafts F rotate in opposite directions and toward each other, (see arrows). As the boat is propelled along, the shafts F, will scoop or throw out the mud or sand each side ofthe boat, the depth of the excavation being regulated as 'desired by adjusting the shafts F, F, at a greater or less height.

This improvement will be extremely valuable for removing sand bars in harbors, or cutting channels through them; also for deepening channels. It is well known that bars often appear and disappear; portions of harbors and rivers will be deep at one period and shallow at another. The beds of running streams as well as those where the tide ebbs and Hows, are continually changing as regards depth. This. varying of depth is caused by the action of tides, currents, eddies, etc. By my improvement advantage is taken of the action of the tides and currents, and the shallow places 'may be readily deepened.

This improvement, it will be Seen, is essentially different from a dredging machine, as no mud or sand is brought up within the My mal chine is designed to eXcavate or throw aside the portion of the bed or river where a channel is to be deepened; the mud or sand being thrown up at each side of the channel as it is scooped out, so that said mud or sand will be carried away to other Spots or localities by eddies, the tide, or by currents.

I am aware that screw shafts have been proposed for use as snow clearers on rail- F, F, Vin the manner substantially as de# seribed, for the purpose of dredging o1' deepening the channels of rivers, etc.

v E. B. BISHOP.

roads, and therefore I do not claim. them broadly.

`Having thus described my invention, what I claim as new, and desire to secure by Let- 5 ters-Patent, is: Witnesses:

The combination with the bow of the R. A. GRAY, boat A, of two spirallyV flanehed shafts, HENRY LACY.

[FIRST PRINTED 1912.] 

